Sorry for the spelling mistake, didn't mean "Fist" but "First" My apologies cheers, rawfiner
Le mer. 12 sept. 2018 à 18:59, rawfiner <rawfi...@gmail.com> a écrit : > Hi Aurélien > > Fist, thank you for showing me this interesting video. > I just compiled your branch. > > My first question is, is it possible to find shift power slope values that > reproduce the result we had before with linear and gamma? > If yes, I think you should compute the new parameters values from the old > ones. > You can take a look at function "legacy_param" in denoiseprofile.c to see > an example. > If that is not possible, we could imagine to have a "mode" selector in the > GUI to switch between "linear and gamma" and "shift power slope". > > Considering opencl, I cannot help you here as I have never coded in opencl > and I do not have a GPU. > Yet, even without opencl, code seems already quite fast. > > Considering the code itself, my only remarks are for this line: > for(size_t k = 1; k < (size_t)ch * roi_out->width * roi_out->height; > k++) > First, is there a reason why you are using a size_t type? int or unsigned > would be fine I think, and you wouldn't need a cast. > Second, in C, array indexes start at 0, so the red value of the pixel at > the top left corner is not processed by your loop (you can see it on > exported image) > > Sso I guess you want the for loop to be: > for(unsigned k = 0; k < ch * roi_out->width * roi_out->height; k++) > > I know that C is hard to learn, so congratulations Aurélien! :-) > > rawfiner > > > Le mer. 12 sept. 2018 à 14:46, Aurélien Pierre <rese...@aurelienpierre.com> > a écrit : > >> Hi everyone, >> >> when working with color profiles, the main historic issue was the >> non-linearity of the sensors/films. Now, it is rather that the color >> profile is performed on a chart having 6-7 EV of dynamic range while modern >> cameras have 12-15 EV. Simple gamma corrections (invented for CRT screens) >> don't work anymore, and video editors have invented a new standard able to >> remap the dynamic range and to fix the mid-tones at once : >> https://www.youtube.com/watch?v=kVKnhJN-BrQ&index=7&list=PLa1F2ddGya_9XER0wnFS6Mgnp3T-hgSZO >> >> I have embedded the formula used in Blender ( >> https://en.wikipedia.org/wiki/ASC_CDL) into the profile correction >> module of dt (using the same parameters for each RGB channel). The result >> looks more natural than the current version, without gamut or saturation >> issues in the highlights. It also speeds-up the worflow, since all is >> needed is this module to adjust the dynamic range, then a tone curve in >> auto RGB mode shaped as a stiff S to bring back the contrast. The result is >> much better than with the tonemapping modules, with less color fixes. >> >> I'm a newbie at C and it's the first time I achieve something inside dt, >> so I could use some reviews on my code and also some help on the OpenCL >> part (the kernel does not load, I don't know why) : >> https://github.com/aurelienpierre/darktable/tree/color-grading >> >> Thanks a lot ! >> >> Aurélien. >> >> ___________________________________________________________________________ >> darktable developer mailing list to unsubscribe send a mail to >> darktable-dev+unsubscr...@lists.darktable.org >> > ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
